Laser wrist with sealed beam pathway

ABSTRACT

A laser beam pathway is established through hollow robotic wrist elements, including plural elements rotatable around first and second wrist axes transverse to one another and intersecting at a junction point. The junction point lies within a mirror chamber formed within a base housing of the robot elements, and a mirror is mounted within the mirror chamber to assist in directing the laser beam. The beam passes collinearly with the first and second wrist axes and first and second ducts are provided with a rotary joint included in the second duct, to isolate the beam pathway from internal wrist drive elements.

BACKGROUND OF THE INVENTION

The invention relates to laser robotics, and in particular relates to alaser robotic system wherein a laser beam is ducted through a laserwrist, having motorized elements. The laser wrist is provided with asealed beam pathway to isolate the beam pathway from the wristmechanism.

Prior art "laser robotic" systems typically employ a passive light pipesystem consisting of a series of light pipes linked at mirrored joints,wherein the initial light pipe is affixed to a laser generator, and thefinal light pipe is attached to the end effector tooling plate of alaser wrist.

Difficulties inherent in prior art assemblies include binding of tbelight pipe system and intrusion of the system with other elements at tbeworkplace cite. Applicants have determined that it would be advantageousto have a fully articulatable laser robot wrist, including internallypowered elements to rotate wrist members around plural drive axes,wherein a laser beam pathway may be established through the wrist, thebeam pathway extending colinearly with the axes of rotation of the wristelements. In certain drive assemblies, it may be desirable to providefull lubrication to rotary members such as, for example, gears andbearings. Additionally, in certain wrist drive mechanism, wear of partsmay cause small particulate contamination of the beam pathway. In orderto provide protection for a laser beam pathway operating under theaforesaid conditions, applicants have obviated the potentialdifficulties in such systems by a novel sealed beam design, wherein alaser robot wrist having an internal beam pathway is provided withsealed beam ducting to isolate the beam pathway from the remainder ofthe internal wrist mechanism.

Additionally, applicants have provided a sealed beam ductway systemthrough an articulatable robotic wrist which may be provided withcooling fluids and the like, which are kept separate from other fluidswhich may be used in or about the internal robotic wrist drive parts.

It is therefore an object of the present invention to provide for afully articulatable robotic wrist having an internal drive mechanism andan internal laser beam pathway, wherein the beam pathway has a sealedbeam ductway to isolate the beam path from the wrist drive mechanism.

Another object of the present invention is to provide a means forisolating laser beam pathway fluids from other fluids which may beutilized in or about internal wrist mechanism parts.

SUMMARY OF THE INVENTION

The invention is shown contained in a laser robotic wrist having a basehousing rotatable around a first wrist axis and a turret housing mountedto the base housing and rotatable around a second wrist axis. The axesare transverse to one another and intersect at a junction point. Meansis provided for mounting the base housing to a laser forearm assemblyand means is provided for driving the turret housing around the secondaxis, wherein the means for driving the housing include drive elementspassing within the base housing. A mirror chamber is provided within thebase housing having a mirror mounted within the mirror chamber. Thejunction point of the two wrist axes lies within the chamber andintercepts the mirror reflecting surface. Continuous laser beam pathwayis established through the base housing, the mirror chamber, and theturret housing, the beam pathway extending colinearly with the first andsecond wrist axes from a beam entrance end defined on the base housing,to a beam exit end defined on the turret housing. First duct means isprovided, enclosing the first wrist axis and communicating with themirror chamber and the base housing beam entrance end. A second ductmeans is provided, enclosing the second wrist axis and communicatingwith the mirror chamber and the turret housing beam exit end. A rotaryslip joint means is provided in the second duct means for permitting theturret housing to rotate with respect to the base housing whilemaintaining enclosure of the second wrist axes, so that the laser beampathway is enclosed with respect to the driving elements passing withinthe base housing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a laser robot assembly, depicting alaser robot, light pipe assembly, and laser generator.

FIG. 2 is a rear elevational view of the laser robot assembly, takenalong the line 2--2 of FIG. 1.

FIGS. 3-6 are side elevational views of the laser robot showing theelements moved to alternate positions.

FIG. 7 is a left side elevational view of the laser robot system of FIG.1.

FIG. 8 is a top plan view of the wrist drive box with cover removed,taken along the line 8--8 of FIG. 7.

FIG. 9 is an elevational section through the forearm pivot jointtaken.along the line 9--9 of FIG. 8.

FIG. 10 is a side elevational section through the wrist drive box takenalong the line 10--10 of FIG. 8.

FIGS. 11-13 are rear elevational sections through the wrist motor driveassemblies, taken along the lines 11--11, 12--13--13, of FIG.8.

FIG. 14 is a left side elevational section of a laser wrist having threeroll axes and a sealed beam path.

FIGS. 14a and b are enlarged sections through the elements of FIG. 14.

FIG. 15 is a diagrammatic view depicting the geometry of FIG. 14.

FIG. 16 is a diagrammatic view through a laser robot wrist having tworoll axes and a sealed beam path.

FIG. 17 is a diagrammatic view through a laser robot wrist having threeroll axes.

FIG. 18 is a diagrammatic view tbrough a laser robot wrist having tworoll axes.

FIG. 19. is a plan section through the laser beam combiner, taken alongthe line 19--19 of FIG. 1.

FIG. 20 is an elevational view of the laser beam combiner, taken alongthe line 20--20 of FIG. 1.

FIG. 21 is a plan view of the beam switcher, taken along the line 21--21of FIG. 1.

FIG. 22 is a side elevational view of the beam switcher, taken along theline 22--22 of FIG. 21.

FIG. 23 is a plan view of the beam switcher mechanism with coverremoved.

FIG. 24 is an elevational view of the beam switcher mechanism takenalong the line 24--24 of FIG. 23.

FIG. 25 is an elevational section through the beam switcher mirrorswinging drive taken along the line 25--25 of FIG. 23.

FIG. 26 is a plan section through the mirror adjusting assembly of thebeam switcher, taken along the line 26--26 of FIG. 24.

FIG. 27 is an elevational view of the backside the mirror adjustingassembly of the laser beam switcher, taken along the line 27--27 of FIG.23.

FIG. 28 is a side elevational section through the unrotating beamdiverter corner assembly of FIG. 1.

FIG. 29 is an auxiliary view of the mirror adjustment assembly, takenalong the line 29--29 of FIG. 28.

FIG. 30 is a side elevational section through an alternate beam divertercorner assembly.

FIG. 31 is a partial side elevational section through the beam diverterrotating corner assembly of FIG. 2.

FIG. 32 is a side elevational view of a laser robot wrist having a beamfocus assembly.

FIG. 33 is a side elevational view of a laser robot wrist havingexemplary laser tooling.

DESCRIPTION OF THE PREFERRED EMBODIMENT General Description of the Robot

FIG. 1 of the drawings illustrates a right side elevational view of alaser robot 10 having a laser generating unit 11 mounted on a floornesrby. The laser unit 11 may be any of a variety of industrial lasingunits manufactured by companies such as Coherent General Company,Spectra-Physics, etc. The preferred laser unit 11 for many powerapplications is a CO₂ gas laser, emitting a laser beam 12 along ahorizontal path from the exit end 13 of the unit 11. The beam 12 isdirected into a beam combiner 14, exiting through a light pipe 15 whichis a hollow tube connected to the beam combiner 14 and to apath-direction changing unit such as the laser beam diverter, or cornermirror assembly 16 shown. The beam combiner 14 will be fully discussedin conjunction with FIGS. 19 and 20, to describe how the robot is cooledand how the beam 12 is aligned. The mirror fixed assembly 16 directs thebeam 12 downward along a vertical path through a light pipe 17 to asecond mirror assembly 16 which redirects the beam 12 along a horizontalpath through a light tube 18 into the base 19 of the robot 10. The lightpipe 18 may be continuous in many applications, but for the preferredembodiment the pipe 18 may be replaced by two pipe sections 18a,b, witha beam switching box 20 located therebetween. The switching box 20 willbe fully described in connection with FIG. 21.

The base 19 of the robot 10 has a shoulder unit 21 mounted to its topside 22, where the shoulder unit 21 is rotatable around a centralvertical axis 23 passing through the base 19. The laser beam 12 isdirected from a mirror assembly 16 within the robot base 19 upward alongthe vertical base axis 23 through a fourth light pipe 24. The initialfour light pipes 15, 17, 18, 24 are fixed with respect to the base 19and floor 19(a). The shoulder unit 21 of the robot 10 essentiallyconsists of a turntable 25 swivelable on the base 19, and a bracket 26affixed to the turntable 25 has a horizontal pivot axis 27 forsupporting a brachium, or upper arm 28, of the robot 10. The shoulderunit 21 supports a drive unit 29 which powers the brachium 28 in apivoting motion relative to the shoulder unit 20. The brachium 28 has ahorizontal pivot axis 30 at its topmost end, where a special forearm 31is journalled on the pivot axis 30 for an elbow joint 30a, so that theassembly may be flexed and extended relative to tbe base 19. Thebrachium 28 also carries a drive unit 32 which is connected to thbrachium 28 and to the forearm 31 to provide for pivotal movement of theforearm 31. The rear end of the forearm 31 carries a drive box unit 33for providing rotary motion to a wrist 34 carried on the forward end ofthe forearm 31. The wrist 34 basically consists of three parts, a baseunit 35, a turret unit 36 and an end effector unit 37, each havingserial roll movements which may be variously combined with one anotherin accordance with the drive box 33. The base unit 35 of the wrist 34 isrotatable about a first roll axis 38 coaxial with the forearm axis 39.The base unit 35 carries the turret unit 36 on a face angled withrespect to the first roll axis 38 and the turret unit 36 is rotatablearound the second roll axis 40 which is oblique to the first roll axis38. The turret unit carries the end effector unit 37 or tooling plate,which is rotatable about a third roll axis 41, in turn obliquelyoriented with respect to the second roll axis 40. The end effector unit37 carries tooling unique to the work assignment.

Referring to FIG. 2, in conjunction with FIG. 1, the vertical light pipe24 extending through the base 19 is rotatably mated with a mirrorassembly 16 at its topmost end, which is rigidly mounted within theshoulder bracket 26, and may rotate about axis 23 with respect to base19. The mirror assembly 16 causes a 90° direction change of tbe beam 12through a side-extending light pipe 42 which passes through a clearancehole 43 in the bracket 26. The upper part of FIG. 2 shows thatside-extending light pipe 44 is rigidly connected to a 90° mirrorassembly 16 mounted on the forearm central axis 39. The side-extendingupper light pipe 44 is connected to a swivel mirror assembly 45 as isthe lower light pipe 42.

In order to accomplish movement of the upper arm 28 relative to theshoulder unit 21, the light pipe assembly must be able to accommodaterelative movement between the upper and lower side-extending light pipes44,42. To accomplish the movement, FIGS. 1 and 2 illustrate that anarticulate light pipe linkage 46 must span the side-extending upper andlower light pipes 44,42. The linkage 46 consists of a swivel mirrorassembly 45 at the end of each horizontal light pipe havingdirection-changing ability to redirect the beam path 90° to thehorizontal pipes. A first linkage light pipe 47 is connected to thelower swivel mirror assembly 45 and extends alongside the brachium 28from approximately the lower pivot axis 27 to approximately the upperpivot axis 30. The upper end of tbe first linkage light pipe 47 has aswiveling mirror assembly 45 which is capable of receiving the beam 12from the first linkage light pipe 47 and then redirecting it 90° to thehorizontal axis. The swivel mirror assembly 45 of the second, horizontallinkage pipe 48 is connected to a third linkage light pipe 49 which isconnected, in turn, to the swivel assembly 45 of the forearm light pipe44. In the manner shown therefore, it may be appreciated that theforearm 31 and brachium 28 may be flexed about with respect to theshoulder unit 21 of the robot 10, and the linkage light pipes 47,48,49will accommodate the flexing movement, as shown in FIGS. 3, 4, 5, and 6.

FIG. 7 is the opposite side view of the robot of FIG. 1, wherein thewrist drive box 33 and motors M1, M2, M3 are depicted, corresponding tothe respective roll axes. The brachium drive unit 29 consists of a screwand nut assembly 50 having an integral drive motor for powering thescrew 51 relative to the nut 52. The screw 51 is pivot-mounted to abracket 53 on the brschium 28 and the nut 52 is pivot-mounted to theshoulder joint bracket 26 so that the screw and nut travel may beaccommodated while pivoting the brachium 28 relative to the shoulderunit 21. The forearm drive unit 32 consists of a screw and nut assembly54 powered by an electric motor wherein the nut 55 is pivotally affixedto a bracket 56 on tbe brachium 28 and the screw 57 is pivotally affixedto a bracket 58 on the forearm 31 so that travel of the nut and screwmay be accommodated while the forearm 31 is pivoted witb respect to thebrachium 28. The side-extending drive motors M1, M2, M3 of the wristdrive box 33 serve to provide rotary motion to each of the serial rollmembers 35, 36, 37 of the wrist 34 with respect to the nonrotatableforearm 31.

Forearm and Elbow Joint

FIG. 8 is a plan view of the (uncovered) wrist drive box 33 which iscarried by the forearm 31. The forearm 31 is nonrotating, and consistsprincipally of a cylindrical tube 59 having an end flange 60 weldedtbereto. The end flange 60 is bolted to a first drive box 33a which, inturn, carries a second drive box 33b. A plurality of cap screws 61spaced around the flange 60 serve to hold the first drive box 33a inposition. The sectional view of FIG. 9 shows the pivot axis 30 and elbowjoint 30a of the robot 10. The forearm 31 has a pair of parallel,diametrically-spaced plates 62,63 extending to the same side, i.e.substantially tangential to the forearm tube 59. The plates 62,63 arebored in line, and receive a pair of stub shafts 64. The shafts 64 havea pilot diameter 65 received in the plate bore 66, and an adjacent shaftflange 67 is bolted by cap screws 68 to the plate 62,63. The shaft 64 isprovided with successively stepped bearing diameter 69, thread diameter70, and outboard end diameter 71 extending from the flange 67 into thebrachium or upper arm 28. The brachium 28 has a clearance diameter 72extending partially over the flange 67 and bearing diameter 69, and abearing bore 73 is provided in the brachium 28 to receive the cup of atapered roller bearing 74. The cone of the bearing 74 is received on thebearing diameter 69 of the shaft 64, and a nut 75 is received on thethreaded diameter together with a seal ring 76. The nut 75 thrusts theseal ring 76 against the cone of the bearing 74. The brachium 28contains a pair of seals 77 which bear respectively on the outerdiameters of the seal ring 76 and the flange 67. Therefore, the bearing74 may be packed with lubricant and sealed from contaminants. Theoutboard diameter 71 of the shaft 64 is connected to an encoder (notshown:) to provide rotational feedback signals indicating forearmposition relative to the brachium 28. The brachium 28 is of bifurcated,ladder-type, construction, that is, a pair of spaced parallel squaretubular members 28a,b extend from the shoulder unit 21 to the elbowjoint 30a.

Wrist Drive Unit

The elevational section of FIG. 10 illustrates that the forearm flange60 is bolted to a machined surface 78 on the first drive box 33a, and aspacer or fitting washer 79 is provided between the two. The flange 59has a pilot diameter 80 with a concentric O-ring seal 81 received in abore 82 in the first drive box 33a. The pilot diameter 80 supports atapered roller bearing 83 and a cylindrical seal 84. A first drive tube85 extends through the forearm 31 to provide the first roll movement tothe base unit 35 of the wrist 34, and a hollow shaft 85a is welded tothe end of the drive tube 85. The hollow shaft 85a extends generallybetween side walls of the drive box 33a. The hollow tube is received inthe roller bearing 83 and seal 84 of the forearm flange 60.

The first and second drive boxes 33a,b, are bolted to one another by aplurality of cap screws 86, and location is provided between the two bymeans of a stubby locating ring 87, having its central flange 87a boltedto the second drive box 33b and piloted i the first box 33a. A shortshaft section 87b extends from the flange into the first drive box 33aand supports a roller bearing 88 and seal 89. The outboard end of thefirst drive tube hollow shaft 85a is received in the roller bearing 88and seal 89. Thus, the hollow shaft 85a is supported at both ends andserves to seal the interior of the first drive box 33a so that lubricantmay be contained therein. A first worm wheel 90 is received on alocating diameter midspan the support bearings 83,88 of the hollow shaft85a, and is held by cap screws 91. A worm support bracket 92 is mountedwithin the first drive box 33a and serves to carry a worm 93 passingacross the upper portion of the worm wheel 90. The first drive box 33ahas a drain plug 94 in the bottom wall so that lubricant may be removed.The plan view of FIG. 8 shows that the worm support bracket 92 ispositionable by means of cap screws 95 passing through an adjusting slot96 and received in the drive box 33a.

FIG. 11 shows that the first drive box 33a has a radius wall section 97conforming to the worm wleel 90, and a pair of side pads 98,99 aremachined in the drive box 33a to serve as a mounting for the wormsupport bracket 92. The worm support bracket 92 is a fabricatedassembly, having foot plates 92a extending across the mounting pads98,99. The foot plates 92a are situated on shim plates 100 which areground to adjust the centerline of the worm 93 with respect to the wormwheel 90. The worm support bracket 92 has parallel side plates 92bextending across the span of the foot plates 92a, and end plates 92csecured to both the side plates 92b and foot plates 92a serve as bearingsupports. Each end plate 92c has a bearing bore to receive the cup of atapered roller bearing 101. The first bearing bore 102 (nearest thedrive end) is machined to a shoulder 103 within the end plate 92c, whilethe second bearing bore 104 is machined through the other end plate 92c.The worm 93 is provided with end bearing diameters and adjacentshoulders to be received with the bearings 101. The bearings 101 areloaded against one another by means of a loading ring 105 received inthe second bearing bore 104 and held in position by a plurality of capscrews 106 and washers 107 received with the second end plate 92c. Thedrive end of the worm 93 is provided with a key 108. The side wall ofthe drive box 33a has a clearance bore 109 at the drive end of the worm93 where the first roll drive motor M1 is affixed to a mounting plate110 by a plurality of cap screws 111. The mounting plate 110, in turn,is affixed to the outer surface 112 of the drive box 33by screws 113 andwashers 114 (FIG. 8), with the shaft 115 of the motor M1 in line withthe worm 93. The motor shaft 115 is provided with key 108, and acommercial coupling 116 serves to connect the motor shaft 115 and worm93. The horizontal mounting pads 98,99 in the drive box 33a haveadjacent vertical walls 98a, 98b and downwardly-extending sections 92dand of the foot plates 92a are slidably fitted thereto and serve totransmit the end thrust of the worm 93 directly to the drive boxstructure. The opposite side of the drive box 33a is provided with asight gage 117 so that lubricant level may be detected.

Referring back to FIG. 10, the second drive box 33b is seen as a castmember having dual cavities 118,119 formed by a central wall 120 andcast bosses 121,122 within the drive box 33b. The two cavities 118,119have drain plugs 94 at their bottommost points. The first cavity 118,adjacent the first drive box 33a, has a bearing 123 and a seal 124mounted within the cast boss 121 adjacent the central wall 120. A seconddrive tube 125 extends through the bore 85b of the first drive tube 85,to provide the second roll movement to the turret unit 36 of the wrist34, and a hollow shaft 125a is welded to the end of the second drivetube 125. The hollow shaft 125a is received in bearings 123, 126 andseals 124, 127. Respectively, mounted in the boss 121 and locating ring87. A second worm wheel 128 is mounted to the shaft 125a against ashoulder mid-span the bearings 123,126 and cap screws 129 connect theworm wheel 128 to the shaft 125a. A second worm 130 passes across theupper portion of the worm wheel 128 and is mounted in a worm supportbracket 92.

The end cavity 119 of the second drive box 33a likewise has bearing 123and seal 124 within the boss 122 adjacent to the central wall 120. Anend mounting plate 131 is received in the outer wall 132 of the drivebox 33b. The mounting plate 131 has a pilot diameter 133 sealed by anO-ring 134 within the drive box wall 132. A flange 135 is receivedagainst a fitting washer 136 and is secured by plurality of cap screws137 and washers 138. A bearing 139 and twin seals 140 are mounted in theinterior face of the end mounting plate 131. A third drive tube 141extends through the bore 125b of the second drive tube 125 and serves toprovide the third roll movement of the end effector 37 of the wrist 34.The third drive tube 141 is welded to a short, hollow shaft 141a in amanner similar to that of the first and second drive tubes 85,125 andthe hollow shaft is received in bearings 123,139 and seals 124,140respectively mounted in the boss 122 and end mounting plate 131. A thirdworm wheel 142 is mounted to the hollow shaft 141a against shouldermid-span the bearings 123,139 and affixed thereto by cap screws 143. Athird worm 144 passes across the upper portion of the worm wheel 142 andis carried in a worm support bracket 92 within the second cavity 119.Referring to FIGS. 12 and 13, the second and third worms 130,144 aremounted in their respective brackets 92 in an almost identical fashionto that of the first worm 93. The second and third drive motors M2,M3are received with mounting plates 110 which are in turn affixed to thesecond drive box 33b. A sight gage 117 is provided at each cavity118,119 to indicate the level of lubricant. A counterbore 145 in in theend mounting plate 131 serves as a clearance relief around the end ofthe third hollow shaft 141a. A reduced-diameter extension 146 isprovided on the plate 131 adjacent the flange 135, and a centralclearance hole 147 runs through the extension 146 and a tube 148 whichis threadably received with the extension 146. Thus, fluid comnunicationmay be had between the hollow threaded tube 148 and the third drive tube141. As will be discussed later, a cooling fluid, such as air, may becirculated through the threaded tube 148. To prevent mingling of theinternal lubricant of the drive box 33 with a cooling fluid, the twinspaced-apart fluid seals 140 are received with the seal diameter 149 ofthe hollow shaft 141a. An internal drain groove 150 is provided withinthe end plate 131 between the seals 140 and a vent hole is drilled inthe end plate extension 146 to connecting the drain groove 150 to theoutside. The seals 140 are turned with their lips facing in oppositedirections to provide the most positive sealing for fluid directedagainst the seals 140. Any slight leakage which may escape the drive box33b will therefore drip into the drain groove 150 and be vented to theoutside rather than mixing with the cooling air of the robot 10. Thecooling air must be kept contaminant-free to provide for the besttransmission of the laser beam 12 through the drive tubes. The threadedtube 148 supports a 90° mirror assembly 16 which is affixed to the tube148 by a lock nut 151. The upper side-extending light pipe 44 is shown(with hidden lines) extending through a hanger bracket 152 affixed tothe outside of the second drive box 33b.

Referring to FIG. 8, the hanger bracket 152 is secured to bosses 153 onthe second drive box 33b by a plurality of cap screws 154, and theoutboard portion of the hanger bracket 152 has a tubular support collar155 sized to fit the light pipe 44 and held to the hanger bracket 152 bya plurality of cap screws 156.

Wrist Unit

Additional references, i.e. left, upper, horizontal, etc. are made forconvenience only in following the respective moved through a widevariety of spatial orientation.

Referring to FIG. 14, and the enlarged views of FIGS. 14a,b, thenon-rotating forearm 31 of FIG. 10 concludes at an enlarged tube head200 welded to the tube 59. The head 200 supports a pair of angularcontact ball bearings 201. The bearings 201 are held in the tube 200 bya bearing retainer cap 202 fastened to the front of the head 200, andloading the bearings 201 against an internal spacer 203 seated againstan internal snap ring 204. The end of the first drive tube 85 is weldedto a tube head 205, which is piloted inside the drive tube 85 and has acentral clearance hole 206. The outer diameter of the tube head 205 issmoothly finished and provided with a slight entry taper to ride in aseal 207 carried by the forearm tube head 200. The first drive tube head205 is connected to the wrist 34 by means of a base unit adapter ring208. The base housing 209 of the wrist 34 is a casting having a mountingflange 210 and adjacent pilot diameter 211. The pilot diameter 211 isreceived in the adapter ring 208 and cap screws 212 secure the flange210 to the ring 208. The adapter ring 208 has a bearing diameter 213 onits opposite side terminating at a shoulder diameter 214 which isadjacent to the outer diameter of the adapter ring 208. A clearance bore213a is provided through the center of the ring 208 in line with theclearance hole 206 of the first drive tube head 205. A plurality of capscrews secure the adapter ring 208 to the drive tube 85. The tube head205 and adapter ring 208 are both received in the angular contactbearings 201 carried by the forearm 31. A spacer 215 is received on thebearing diameter 216 of the tube head 205 against the inner races of theangular contact bearing 201. A second seal 207 is received in the frontof the bearing retainer cap 202 and is in rotating contact with theshoulder diameter 214 of the adapter ring 208, to protect the bearings201 from outside contaminants.

For assembly reasons, the adapter ring 208 is secured to the bearings201 and first drive tube 85 before the base housing 209 is mounted tothe adapter ring 208. But, for practical purposes, it may be assumedthat the adapter ring 208 and base housing 209 function as if they areintegral with one another.

Actuation of the first drive motor M1 (see FIG. 8) causes rotationalmovement of the first drive tube 85 with respect to the nonrotatingforearm 31 and, consequently, the entire wrist 34 is rotated with thebase housing 209. The second drive tube 125 of FIG. 10 extendsconcentrically within the first drive tube 85, and has an internallysplined tube head 217 welded to the end of the tube 125. The tube head217 has an outer diameter sized to fit easily through the clearance bore206 in the first drive tube head 205. A rear counterbore is provided inthe tube head 217 to fit closely over the second drive tube 125, forwelding. The front of the tube head 217 has a reduced outer diameter andan internal spline 218 is machined centrally through the tube head 217.The base housing 209 supports internal bearing package 219 consisting ofspaced-apart angular contact ball bearings 220 carried in a flangedbearing sleeve 221. The bearings in turn, carry a drive spindle 222. Thespindle 222 has a main bearing-supported diameter 223, and an adjacentshoulder 224 on the interior end blends to a first bevel gear 225machined about the end of the spindle 222. The bearing diameter 223concludes at a threaded portion which is subsequently reduced to a sealdiameter 226. The threaded portion maintains a bearing locknut 233. Theseal diameter 226 continues for a short length and is tapered down tosmaller external splines 227. A clearance hole 228 is provided throughthe spindle 222 and a first, shallow depth bearing bore supports abearing 229 in the gear end of the spindle while a second, longer depthbearing bore supports a bearing 229 in the splined end of the spindle222. A seal ring 230 is received on the bearing sleeve 221 and heldtherewith by a plurality of cap screws 231, and the seal ring 230contains a seal 232 which runs with the spindle seal diameter 226 toisolate the bearing package 219 from rear portions of the assembly. Whenthe base housing 209 is affixed to the adapter ring 208, the externalsplines 227 are slipped into engagement with the internal splines 218 ofthe second driver tube 125. The central first roll axis 38 of the wristbase housing 209 is concentric with the axis 39 of the forearm 31.

The base housing 209 has a machined 233 face normal to a second rollaxis 40 which is angled relative to the central first roll axis 38 ofthe housing 209. It may be appreciated that, while the preferredembodiment of FIG. 14 depicts the first and second roll axes 38,40 asbeing obliquely oriented to one another, tbey may be constructed atright angles, as well. A bearing bore 234 is machined in the face 233,concentric with the second roll axis 40, and contains a single turntablebearing 235 which is used to provide antifriction support for the turretbousing 236 of the wrist 34. The turret housing 236 is a cast bodyhaving a bottom face 237 in line with the inner race of the turntablebearing 235. A bearing diameter 238 on the housing 236 is received inthe turntable bearing 235 extends to a shoulder 239 which is adjacent toa seal ring 240 fitted on the housing 236. A fitting washer 241 isreceived between the shoulder 239 and bearing 235, and the turrethousing 236 is secured to the bearing 235 by a bearing clamp ring 242held to the bottom face 237 by cap screws 243. The outer race of theturntable bearing 235 is secured in position with the base housing by abearing retainer 244 affixed to the oblique face 233 of the base housing209 by a plurality of cap screws 245. The top side of the bearingretainer 244 contains a seal 246 mounted in sealing contact with theseal ring 240 of the turret housing 236. A thin outer cover plate 247 issecured to the outer surface of the bearing retainer 244 to secure theseal 246 in position and to help exclude contaminants. A second bevelgear 248 is pilot-mounted into the bottom face 237 of turret housing 236and backed up by a fitting washer 249. A plurality of cap screws 250 areprovided from the upper side of the turret housing 236 to secure thesecond bevel gear 248. The second bevel gear 248 is in mesh with thefirst bevel gear 225 of the spindle 222 carried in the base housing 209.Therefore, it can be seen that rotation of the second drive tube 125causes rotation of the base housing spindle 222 about the first rollaxis 38, and simultaneous rotation of the turret housing 236 about thesecond roll axis 40. The rotation of the turret housing, of course,causes the end effector 37 to rotate around the second roll axis 40, aswell.

A second tubular spindle 251 is rotatably carried about the first rollaxis 38 by a concentric mounting within the bearings 229 contained inthe first tubular spindle 222. The inner end of the second tubularspindle 251 has an integral bevel gear 252 and a central counterbore253. A bore 254 is provided through the entire length of the secondtubular spindle 251. The second tubular spindle 251 is shoulderedagainst a fitting washer 255 at the inboard bearing 229, and the spindle251 extends through both bearings 229 and concludes at a threadedportion which maintains a locknut 256 and washer 257. The spindle 251 isfurther reduced to a smooth seal diameter 258 and adjacent, exteriorsplines 259. The exterior splines 259 are further reduced to a sealdiameter 260 containing an O-ring 261. A spacer tube 262 is carried onthe spindle 251 between the inner races so that the bearings 229 willnot be overloaded in assembly. A cylindrical seal 263 carried in thebearing bore of the first spindle 222 is in sealing contact with theseal diameter 258 of the second spindle 251.

The third drive tube 141 shown in FIG. 10 extends concentrically withinthe second drive tube 125, and terminates at a tube head 264 similar indesign to the second drive tube head 217. The tube head 264 is pilotedwithin the third drive tube 141, and a central flange abuts the end ofthe tube where it is welded. The forward end of the head 264 has areduced diameter upon which is mounted a support ring 265, closelyfitted within the interior splines 218 of the second tube head 205 tosupport and guide the tube 141 when the wrist 34 is removed. The thirdtube head has a smooth fitting bore 266 received on the seal diameter260 and O-ring 261 of tbe spindle 251, and has interior splines 267machined to fit with the exterior splines 259 of the spindle 251. Thus,when the base housing 209 of the wrist 34 is affixed to the adapter ring208 and the first spindle splines 227 are received with their matingsplines 218, the second spindle splines 259 will also be received intheir mating interior splines 267.

A third spindle 268 is rotatably carried in a bearing pack 269 mountedwithin the turret housing 236 concentric with the oblique second rollaxis 40. The spindle 268 has a central clearance bore 270 anddownward-opening counterbore 271, and a fourtb bevel gear 272 ismachined on the top end of the spindle, i.e. adjacent to the upperbearing 273 of the bearing pack 269. The bearing retainer 269a is aflanged cylindrical member received in a smooth bore in the turrethousing 236 and held by screws. The spindle 268 extends through bothbearings 273, beyond the lowermost bearing 273. A second bevel gear 274is received on tbe spindle 268 against a fitting washer 275 and lowerbearing 273 and held to the spindle 268 by cap screws. The bevel gear274 thus also serves as a bearing retainer and is used to load thebearings 273 against a tubular bearing spacer 276. The lower bevel gear274 has a central bore equipment to the spindle counterbore 271 and isin mesh with the gear 252 of the second spindle 251.

A fourth spindle 277 is also carried in a bearing pack 278 and rotatableabout the third roll axis 41, which is oblique to the second roll axis40, in the turret housing 236 by the bearing pack 278 comprises a pairof spaced-apart bearings 279 mounted in opposite end bores of a flangedbearing retainer 280, and the retainer 280 is closely fitted into a borein the turret housing 236. The bearing retainer 280 is seated against afitting washer 281 on the front face of the turret housing 236. Theretainer carries a seal 282 in front of the outer bearing 279. The innerend of the spindle 277 is provided with a bevel gear 283 which isenmeshed with the upper bevel gear 272 of tbe third rotatable spindle268. The spindle 277 is step counterbored at the gear 283, around acentral clearance bore 284. The spindle 277 extends into the outerbearing 279 and is provided with a smooth entry bore 285, increasing toa central relief diameter 286 terminating at the approximate axialmidpoint of the spindle 277. The smooth bore 285 receives the pilot 287of an end effector tooling plate 288. The end effector plate 288 has anouter flange 289, stepping down to a seal diameter 290, which isreceived in the bearing retainer seal 282. The seal diameter 290 isfurther reduced to a face-relieved bearing surface 291 which abuts theouter bearing 279 of the bearing pack 278, and terminates at the smallerpilot 287. The pilot 287 and main diameter of the bearing retainer 280each have a circumferential O-ring seal 292,293. A fitting washer 294 isplaced between the end of the spindle 277 and the bearing surface 291 ofthe end effector plate 288 to prevent over-tightening, and a pluralityof clamping screws 295 are provided through the washers 296 received inclearance counterbores 297 in the front face 298 of the end effectorplate to secure the plate 288 to the spindle 277. A bearing spacer 299is provided over the spindle 277 between the inner races of thespaced-apart bearings 279. An outer dust seal 300 bears on the O.D. ofthe end effector f-ange 289 and a wear plate 301 on the front face ofthe bearing retsiner 280.

A hollow cylindrical internal boss 302 on the cast turret housing 236,extends into the area formed between tbe angled spindles 268,277. thecenterline 303 of the boss 302 bisects the included angle beta betweenthe second and tbird roll axes 40,41. The inner end 304 of the boss 302is closed, and has two flat, symmetrical faces 305,306 normal to therespective axes 40,41. The faces 305,306 are provided with a pair ofbores 307,308 at the 5 o'clock and 9 o'clock positions, coaxial with therespective second and third roll axes 40,41, respectively, and a pair ofseal tubes 309,310 extend from the boss 302 colinearly with the rollaxes 40,41. The first seal tube 310 is tightly received in the bore 308of the housing boss 302 and has a seal diameter 311 extending through atube seal 312 in the counterbored fourth spindle 277. The seal tube 310has a central clearance hole 313 so that an unobstructed path is formedalong the third roll axis 41 through the spindle 277, end effector plate288, and seal tube 310.

A hollow, generally cylindrical boss 314 on the cast base housing 209,normal to the first roll axis 38, extends into the area formed betweenthe second and third spindle 251,268. The boss 314 branches into twoside bosses 314a,b, at the 3 o'clock and 11 o'clock positions, havingbores 315,316 coaxial with the first and second roll axes 38,40respectively. The first bore 315 receives a seal tube 317 which ispressed into the bore 315 and has a seal diameter extending into a seal318 carried in the second spindle 251. A central clearance hole 319through the seal tube 317 serves to provide an unobstructed path alongthe first roll axis 38 through the second spindle 251 and seal tube 317,to the interior of the base housing boss 324. The second bore 316 of thebase housing boss 314 contains a hollow support sleeve 320 which carriesa tube seal 321. A seal tube 322 pressed into the bore 307 of the turrethousing boss 302 extends through the tube seal 321 of the base housing209. The seal tube 322 has a central clearance hole 323 so that anunobstructed path is maintained through the seal tube 322 and supportsleeve 320, interconnecting the bores or interior chambers 324,325 ofthe turret housing boss 302 and base housing boss 314.

The three rotary slip joints A, B, C, are therefore created along thefirst, second and third roll axes 38, 40, 41, so that an interior besmpath may be completely isolated from the gear drive mechanism of thewrist 34. The isolation of the mechanism from the interior path isdesirable, in many cases, because lubricant in the form of liquids, drysolids, oil mist, etc., may interfere with the transmission of the laserbeam 12.

The outer surface 326 of the base housing boss 314 is machined flat andprovided with the finished bore 324, forming the closed interiorchamber. A reflecting mirror assembly 327 is received in the bore 324and is generally comprised as follows: an adjusting base 328 has acylindrical body received in the bore 324 and sealed with an O-ring 329,and a flange 330 is secured against the finished surface 326 of theboss. A plurality of set screws 331,332 are received in a circularpattern around a gimbal rod 333 which passes through the adjusting base328 along a centerline 334 displaced from the centerline 335 of the boss314. The gimbal rod 333 is, basically, a long screw having a smoothdiameter terminating at a head 336, and a spherical bearing 337 isreceived on the diameter against the head 336. The outer race of thespherical bearing 337 is snugly received in a counterbore 338 of acylindrical mirror mounting block 339. The counterbore 338 meets with aclearance hole 340 through the block so that the block 339 may beswiveled about the spherical center 341. The spherical center 341 islocated along the bisector line 342 of angle alpha, the included anglebetween the first and second roll axes 38,40. The mounting block 339 isreceived in an adjustable block 343 in turn seated against the adjustingscrews 331,332. The sdjustable block 343 has a surface 344 mitered offparallel to a line normal to the bisector line 342 of angle alpha. Thegimbal rod 333 is threaded at its bottom end, and a tension spring 345is seated in a counterbore 346 and held on the rod 333 by a washer 347and nut 348, to bias the adjustable block 343 against the screws331,332. The outer end of the gimbal rod passes through a cover washer349 and a pair of jam nuts 350 to enclose the spring assembly. Themirror mounting block 339 is cylindrical about the bisector line 342having a concentric pilot 351 received in a bore in the mitered surface344 of the adjustable block 343. The outer diameter of the mirrormounting block 339 is threaded to receive a retaining cap 352 whichholds a flat cylindrical mirror 353 securely in position. The mirror 353is adjusted until the mirror reflecting surface 354 accurately passesthrough the intersection point 355 of the first and second roll axes38,40 and lies at an angle which reflects the laser beam 12, receivedalong the first roll axis 38, to the second roll axis 40.

The boss 302 of the turret housing 236 is machined with a flat exteriorsurface 356, and a bore 325 extends therein, forming the interiorchamber, along line 303 bisecting the angle beta formed between thesecond and third roll axes 40,41. In a manner similar to that describedin connection with the base housing 209, the turret housing 236 also hasan adjusting base 357 received in the bore 325 and having a flange 358bolted to the surface 356. The gimbal rod 333 passes centrally throughthe adjusting base 357, and a plurality of adjusting screws 331,332 arereceived in a circular pattern around the gimbal rod 333. A sphericalbearing 337 is held on the gimbal rod 333 against the head 336 and thebearing outer race is received in a bore 359 in the mirror mounting base360, reacting against a plate 361 fastened to the base 360. Plate 361has a clearance hole 362 to permit the mirror 353 swivel. The frontsurface of the base 360 receives the flat reflecting mirror 353, held bythe retainer cap 352 threadably received on tbe outer diameter of thebase 360. The mirror reflecting surface 354 is adjusted io accuratelypass through the intersection point 363 of tbe second snd third rollaxes 40,41 and the surface 354 is angularly aligned so that a laser beam12 passing along the second roll axis 40 will be reflected directlyalong the third roll axis 41. The gimbal rod 333 is provided with thetension spring 345 and adjusting nut 348 and washer 347 received in acounterbore 364 in the back surface of the adjusting block 357 to biasthe mirror assembly against the adjusting screws 331,332.

Diagrammatic Wrist Designs

FIG. 15 illustrates a simplified diagrammatic structure for the wrist ofFIG. 14 wherein three concentric drive tubes, T1, T2, and T3, are drivenby respective drive motors, M1, M2 and M3 in a nonrotating forearm 31.The simplified structure shows that drive tube T1 provides the roll 1movement, i.e., around the roll 1 axis 38. A gear, G1 on drive tube T2serves to provide the rotational movement to the turret unit 36, aroundthe roll 2 axis 40, since gears G1 and G2 (on the turret) are in mesh.In order to provide rotary movement to the end effector unit 37, thecentral drive tube T3 has a gear G3 located at its inboard end, in meshwith the gear G4 of a rotary spindle supported in the turret unit. Thespindle also has a gear G5 at its opposite end, in mesh with gear G6 ofthe end effector unit so that unit will rotate sround the roll 3 axis41. The mirrors 353 are supported as shown in FIG. 14, within therespective turret unit 36 and base housing unit 35. The sealing tubes310, 317, snd 322 are sealed at seal points A, B, and C, to provide aclosed path for the laser beam 12.

An alternate embodiment of the sealed beam path wrist unit of FIG. 15 isshown in FIG. 16, wherein only two roll axes, 38 and 40 are provided. Inthe structure of FIG. 16, therefore, the inner drive tube T3 is omitted,and the sealing tube 317 is sealed with the second drive tube T2 atpoint A. The second sealing tube 322 is sealed at point B along thesecond roll axis 40. The turret housing boss 302 is provided with afixed nonrotating tube 37a, so that there is no rotation around the axis41a as the laser beam 12 exits the wrist 34a. Gears G1 and G2 are usedto provide the roll 2 axis movement to the turret unit 36a. The drivetubes T1 and T2 are shown powered by motors M1 and M2, and motor M3 isomitted.

FIG. 17 depicts an alternate embodiment of the wrist structure wherein athree-roll wrist is depicted without a sealed beam path. Drive tubes T1,T2, and T3 provide the rotational movements around the three-roll axes38, 40, and 41. The mirror supporting bosses 302a, and 314a, aretruncated and serve only for structure support and not for sealing of abeam Path. The mirrors 353 are exposed to the internal mechanism of theunit, and the design is useful for a relatively clean, light duty,geared wrist where potentially deleterious particles are not created tointerfere with the mirrored surfaces and the laser beam path.

FIG. 18 depicts a two-roll axis wrist, where only drive tubes T1 and T2are utilized to provide rotational movements about the roll 1 and roll 2axes, 38, 40. Again, as in FIG. 17, the mirror supporting bosses 302aand 314a are truncated and are used only for structural support and notfor beam path sealing.

With reference to FIGS. 16 and 18, it will be appreciated that it is notnecessary to provide a roll three movement when the tooling unitconsists primarily of a beam focusing unit, 700 (FIG. 32) i.e. a lenssupport structure, serving to produce a focused beam point, and that thethird roll movement is particularly needed when the tooling packageconsists of a unit which must be oriented around a workpiece and thelike. An example of such a tooling unit would be a C-frame spot weldingunit 800 (FIG. 33), wherein a beam path is conducted to the anvilportion 801 of the C-frame 802, and the C-frame 802 must be rotated atvarious times to accommodate a workpiece 803 for clamping purposes.

Laser Beam Combiner

Referring to the plan section of FIG. 19 and the front view of FIG. 20together, the laser beam combiner 14 of FIG. 1 is shown affixed to amounting plate 400 mounted to the front, or exit end 13 of the lasergenerator unit 11. The beam combiner 14 is of welded construction,having a baseplate 401 extending as side flanges 402,403 secured by capscrews 404. The baseplate 401 has a central horizontal hole 405 withclearance around the flange 406 of a laser entry tube 407 flange-mountedwith screws 408 against the baseplate 400. The tube 407 has a centralaperture or bore 409 for the passage of the high power laser beam 12emanating from the laser generator unit 11. The beam combiner 14 has aside plate 410 extending parallel to the laser beam 12, and an end plate411 is aligned at 90° to the side plate 410. The end plate 411 has athreaded collar 412 secured thereto, sealed with an O-ring 413 and thefirst light pipe 15 is threadably received in the collar 412. The sideplate 410 has an aperture or hole 414 and spot face 415 covered by atransparent window 416 which is gasketed and held in position witbbuttonhead screws 417. A relatively low-power laser generator unit418--for example, a helium neon (HeNe) laser, which emits a red visiblelight beam--is mounted at 90° to the side plate 410 on a mountingbracket 419 fastened to the mounting plate 400.

The laser unit 418 is aligned so that the incoming beam 420 will form aright triangle with the axis 421 of the light pipe 15. In order to doso, a base angle alpha is selected, and the apex angle delta would thenbe 90° minus alpha. A reflecting mirror 422 is positioned at the basecorner 423 of the triangle, normal to a line 424 bisecting angle alpha.The mirror 422 is held against the end of a positioning plug 425 by aretaining cap 426 threadably received on the plug 425. The positioningplug 425 has a pilot 427 received in a close-fitting bore 428 in athick, angled side wall 429 of the box 14, and a flange 430 is receivedagainst a fitting washer 431 to adjustably position the mirror 423. Thepilot 427 is sealed with an 0-ring 432, and the plug 425 is held inposition by cap screws 433 received through the flange 430. The end 434of the laser entry tube 407 is machined flat, normal to a line 435bisecting angle delta, and a shallow counterbore 436 in the surface 434receives a gallium-arsenide (GaAs) window 437, which is transparent tothe CO₂ wavelength and reflective to the He-Ne wavelength. This allowsthe CO₂ beam, to pass through to the light pipe while reflecting theHe-Ne beam along the same line which is retained by a retaining ring 438and screws 439. In order to assure that the low power, visible laserbeam 420 is centered coaxially with the axis 421 of the light pipe 15, atooling plug 440 is inserted in a close-fitting bore 441 in the endplate 411 of the box 14. The plug 440 has a knurled outer diameter andhas a small central aperture 442 and a counter-drilled clearance hole443. When the mirror 422 is positioned correctly, the visible beam 420will pass through the aperture 442. This beam 420 is utilized foraligning the various mirrors on the robot 10, since the higher-powermain laser beam 12 is invisible to the eye. After aligning the lasercomponents, the tooling plug 440 is removed, and the low-power laserunit 418 may, optionally, be turned off, or left on to track thelarger-diameter, high-power beam 12. The beam combiner 14 has anadditional side plate 444 enclosing the structure, having a weldedcircular flange 445 and a clearance hole 446 therethrough. A thinmounting plate 447 is gasketed and secured to the flange 445 by capscrews 448, and the mounting plate 447, in turn, supports a vortex tube449 by means of a threaded end 450 passing through the plate 447 andsecured with a locknut 451. The vortex tube 449 is of the type availablefrom the Vortec Company, Cincinnati, Ohio, wherein compressed air entersthrough a side inlet 452 at a first reference temperature. Through avortex/spinning action, cold air will exit one tube end 450 and hot airwill exit the other end 453. The cold air flows through the box 14 anddown through the light pipe 15 to cool the various laser components andto slightly pressurize the system so as to prevent the entry of airbornecontaminants from the atmosphere. The laser mounting bracket 419 alsocarries an air filter 454 and pressure regulator 455 tubed in serieswith the vortex tube 449 to regulate and clean the air received from anair pressure source (not shown).

Beam Switching Box

During periods of the robotic cycle when the laser beam 12 is notneeded, the beam may be routed to auxiliary units such as laser tools orrobots (not shown), connected to an auxiliary light pipe 18c of a beamswitching box 20.

The plan view depicted in FIG. 21 illustrates the square beam switchingbox 20 of FIG. 1, having entry and exit light pipes 18a and 18b securedin position with threaded collars 500 secured to the sides 501,502 ofthe box 20. Of the remaining two sides 503,504 of the box 20, one side503 carries a multi-pin electrical connector 505 for a motor andswitches (FIGS. 23-27) and the other side 504 carries a threaded collar500 sealed with an O-ring 506 and secured with screws 507. A side lightpipe 18c is threadably received in the collar 500 and held thereto by alocknut 508. Since the light pipes 18a,b,c are tubular and do not extendthrough the box 20, it can be seen from the view shown in FIG. 22 thatthe box can be secured to a baseplate 509 by screws 510 received throughthe baseplate 509 and into the sides 501-504.

A mirror 511 is pivotable between closed and open positions 511a,511b toeither reflect the laser beam 12 to the side pipe 18c or pass the beam12 through to the in-line pipe 18b.

Referring simultaneously to FIGS. 23 and 24, the sides 501-504 of thebox 20 are removed for clarity and FIG. 24 shows that the baseplate 509carries a vertical mounting plate 512 attached to a right anglefootplate 513. The vertical mounting plate 512 carries a pair ofidentical right angle bearing blocks 514 on its opposite side, whichcontain bearings 515 (see FIG. 25) to support a vertical pivot rod 516.The pivot rod 516, in turn, carries a mirror gate 517, which is agenerally square vertical plate having side-extending lugs 518 which arebored to fit the pivot rod 516. Saw slots 519 and clamping screws 520secure the gate 517 to the rod 516. The gate 517 is fitted with a pairof fitting washers 521 to take the vertical shake out of the assembly,the lower fitting washer 521 resting against a collar 522 secured to thepivot rod 516. The bottom of the pivot rod 516 extends into a flangedbushing 523 in the baseplate 509. The top of the pivot rod 516 carries agear 524 secured by a hub set screw 525 tightened against a flat 526 onthe rod 516. The top of the vertical mounting plate 512 carries a motormounting bracket 527 which serves to position a drive motor 528 in avertical attitude. The shaft 529 of the drive motor 528 carries a drivepinion 530 secured by a set screw 531, the pinion 530 being in constantmesh with the gear 524. The plan view of FIG. 23 shows that the gate 517is pivotable between the closed position shown in solid, i.e., restingagainst a closed position stop block 532, and an open position shown inphantom, i.e. resting against an open position stop block 533. Threeidentical switch mounting brackets 534 are secured to the baseplate 509,and support identical push button switches 535a,b,c. Two of the switches535a,b are activated or "made" when the gate 517 is in the closedposition, while the third limit switch 535c is activated by a bracket536 (secured to the back of the gate) when the gate 517 is open. As canbe seen in FIG. 24, the closed position of the gate and its controlelements are angled with respect to the baseplate so that an incominglaser beam 12 will be reflected 90° to the side when the gate is closed,and the beam 12 will flow directly through when the gate 517 is opened.

The mirror mounting assembly for the mirror gate 517 is shown in FIG.26, where the circular mirror 511 is positioned in the counterbore 537of a mirror retainer 538, the retainer 538 having a central clearancehole 539 extending therethrough. The counterbore 537 is threaded andreceived on the threaded diameter of a mirror adjusting bracket 540. Thebracket 540 has a cylindrical flange 541 adjacent to the threadeddiameter screwed into the mirror retainer 538, and provided with a stopscrew 542 to prevent overtightening of the mirror 511. The back face ofthe mirror adjusting brackets 540 has a counterbore 543, with a circularfacial groove 544 machined into the bottom thereof, in the shape of anincomplete ring with approximately 60° between the start and stop pointsof the groove 544 (see FIG. 27). A cover plate 545 is seated against thebottom of the counterbore 543 to enclose the groove 544, and pair ofbarbed hose fittings 546 are threadably received in the coverplate toprovide for coolant flow through the groove 544 when it is desired tocool the mirror 511. The outer surface of the mirror retainer 538 isspherical, having a radius swung from the intersection point, orreflecting point 547, of the surface of the mirror 511 at the centerline548. A spherical socket 549 is provided in a square mounting plate 550secured to the back of the gate 517 and accurately positioned with afitting washer 551 to establish the correct adjustment to the mirrorreflecting point 547. The flange 541 of the mirror adjusting bracket 540has three equally-spaced swivel-pad adjusting screws 552 which bearagainst the mounting plate 550, and thereby provide an accurate swiveladjustment of the spherical mirror retainer 538. A plurality ofcommercial spring plungers 553, each having a threaded body andspring-loaded nose, are threadably received in the flange 541 to biasthe mirror retainer 538 in its spherical socket 549. An O-ring 554 maybe provided on the retainer 538 to introduce a slight drag, to preventslippage when adjusting the mirror 511.

Elbow Mirror Assemblies

Referring to FIGS. 1, 28, and 29, the fixed elbow mirror assembly 16 isshown having a main body 600 drilled with intersecting 90° holes601,602. The holes 601,602 are counterbored to receive a threadedbushing 603 which is bonded into place, and the bushing 603, in turn,receives a threaded light pipe adapter 604 whicb is secured by a washer605 and locknut 606. The adapter 604 has a central hole 607 for thetransmission of a laser beam 12, and the smooth outside diameter 608,adjacent to a flange 609, is provided to fit within the counterbore 610of a light pipe 15. A mirror 511 and related mounting unit 611 issecured in a double counterbore at the mitered surface 612 of the elbowbody 600. The mirror assembly is spherically-mounted, as shown in FIG.26 and utilizing the same parts, with the flange of the mounting plate550 secured to the main body 600. In a slight variation to themirror-mounting assembly of FIG. 26, but the functional equivalentthereof, the commercial spring plungers 553 are mounted in the main body600 to bias the mirror retainer 538 into its socket 549.

An alternate embodiment of the fixed mirror assembly 16 is shown in FIG.30, wherein a mirror 353 is supported by structure similar to that ofthe wrist unit turret boss 302 (FIG. 14). The mirror 353 is swivelableabout a spherical bearing 337 journalled on the gimbal rod 333a, and therod 333a is a shoulder screw positioned with its shoulder surface evenwith the bottom of a counterbore 613 in the special mirror adjustingblock 614. The block 614 also serves as a cover for the assembly, havinga flange 615 secured to the main body 616 of the assembly 16, and iscounterbored to receive the mirror 353, mirror mounting base 360, andretaining ring 352. The adjusting block 614 is provided with threeequally-spaced, swivel pad adjusting screws 552 to rock the mirror 353about the spherical bearing 337. A small threaded stud portion 617 onthe end of the gimbal rod 333a receives a pair of washers 618 having astack of disc springs 619 therebetween, and a nut 620 holds the springs619 together. Thus, by the assembly shown, it can be seen that theadjusting screws 552 may be extended to provide a slight preload of thefirst washer 618 against the spring stack as the gimbal rod 333a isthrusted toward tbe reflection point 621.

A rotatable elbow unit 415 is depicted in FIG. 31, wherein the mirrorassembly 622 has a main body 623 having 90° openings 624,625 coactingwith an internal mirror 511. The first opening 624 is provided with astationary adapter ring 603 which is cemented in position (as also shownin FIG. 28). However, the second opening 625 of the main body 623 isprovided with a special tubular adapter portion 626. The adapter 626carries spaced-apart antifriction bearings 627 in a suitable bore, andan adapter tube 628 is carried within the bores of the twin bearings627. The adapter tube 628 is axially positioned by an internal shoulder629. The outer end of the tube 628 extends beyond the adapter portion626 and carries a retaining cap 630, secured by screws 631. The cap 630may comprise an integral part of a continuing light pipe 44. A seal 632is carried in the adapter portion 626 to sealingly engage the adaptertube 628 to prevent the entry of contaminants into the system.

The assembly shown in FIG. 31 therefore permits the elbow unit 45 torelatively rotate around a light pipe 44 while maintaining the accuracyof the mirror setting.

Laser Tooling

FIG. 32 depicts a beam focusing unit 700 affixed to the end effectortooling plate 288, at the beam exit end 701 defined on the plate 288.The focusing unit 700 consists, basically, of a housing, or nozzle 702,supporting a beam-concentrating focus lens 703.

FIG. 33 depicts a C-frame spotwelding unit 800, having a relativelyfixed anvil portion 801 on the C-frame 802, which is brought intocontact relatively with a workpiece 803. The spotwelding unit 800 has abeam focusing portion 804 and a relatively-movable clamp portion 805.The three-roll movement of the wrist unit 34 permits greatmaneuverability for the robot 10 when applying robot tooling.

While the invention has been shown in connection with a preferredembodiment and several alternate embodiments, it is not intended thatthe invention be so limited. Rather, the invention extends to all suchdesigns and modifications as come within the scope of the appendedclaims.

What is claimed is:
 1. A sealed-beam laser wrist, including:a basehousing, having a first wrist axis; a turret housing, mounted to saidbase housing and rotatable about a second wrist axis, transverse to, andintersecting said first wrist axis at a junction point; means fordriving said turret housing about said second axis., said means fordriving including drive elements passing within said base housing; andmeans for mounting said base housing to a laser forearm assembly;whereinthe improvement comprises: a mirror chamber within said base housing,said junction point lying within said chamber; a mirror mounted withinsaid mirror chamber, said mirror having a mirror reflecting surfaceintercepting said junction point; a continuous laser beam pathwaythrough said base housing, said mirror chamber and said turret housing,said beam pathway extending collinearly with said first and second wristaxes from a beam entrance end defined on said base housing, to a beamexit end defined on said turret housing; first duct means enclosing saidfirst wrist axis and communicating with said mirror chamber and saidbase housing beam entrance end; second duct means enclosing said secondwrist axis and communicating with said mirror chamber and said turrethousing beam exit end; and rotary slip joint means in said second ductmeans for permitting said turret housing to rotate with respect to saidbase housing while maintaining enclosure of said second wristaxiswhereby said laser beam pathway is enclosed with respect to saiddriving elements passing within said base housing.
 2. A sealed-beamlaser wrist, including:a base housing, having a first wrist axis; aturret housing, mounted to said base housing and rotatable about asecond wrist axis, transverse to, and intersecting said first wrist axisat a first junction point; a third wrist axis in said turret housing,transverse to, and intersecting, said second wrist axis at a secondjunction point; means for driving said turret housing about said secondaxis, said means for driving including drive elements passing withinsaid base housing; and means for mounting said base housing to a laserforearm assembly;wherein the improvement comprises: a first mirrorchamber within said base housing, said first junction point lying withinsaid first chamber; a second mirror chamber within said turret housing,said second junction point lying within said second chamber; a firstmirror. mounted within said first mirror chamber, said first mirrorhaving a mirror reflecting surface intercepting said first junctionpoint; a second mirror mounted within said second mirror chamber, saidsecond mirror having a mirror reflecting surface intercepting saidsecond junction point; a continuous laser beam pathway through said basehousing, said first and second mirror chambers, and said turret housing,said beam pathway extending collinearly with said first, second andthird wrist axes from a beam entrance end defined on said base housing,to a beam exit end defined on said turret housing; first duct meansenclosing said first wrist axis and communicating with said first mirrorcbamber and said base housing beam entrance end; second duct meansenclosing said second wrist axis and communicating with said first andsecond mirror chambers; third duct means enclosing said third wrist axisand communicating with said second mirror chamber and beam exit end; androtary slip joint means in said second duct means for permitting saidturret housing to rotate with respect to said base housing whilemaintaining enclosure of said second wrist axiswhereby said laser beampathway is maintained enclosed with respect to said driving elementspassing within said base housing.
 3. The sealed-beam laser wrist ofclaim 2, further comprising:a tooling plate, mounted to said turrethousing at said beam exit end, said toling plate rotatable about saidthird wrist axis; means for driving said tooling plate about said thirdwrist axis, said means for driving said tooling plate including driveelements passing within said base housing; and rotary slip joint meansin said third duct means for permitting said tooling plate to rotatewith respect to said turret housing while maintaining enclosure of saidthird wrist axiswhereby said laser beam pathway is maintained enclosedwith respect to said driving elements passing within said base housing.4. An improved laser wrist and forearm assembly for a laser robotcomprising:a base housing, rotatable about a first wrist axis; a turrethousing mounted to said base housing and rotatable about a second wristaxis, transverse to, and intersecting said first wrist axis at ajunction point; a robotic forearm, rotatably supporting a plurality ofconcentric drive tubes rotatable about a forearm axis; means formounting said base housing to one of said drive tubes; means forrotatably driving said tubes; and means for drivingly-connecting anotherof said tubes to said turret housing, said means fordrivingly-connecting including drive elements passing within said basehousing;wherein the improvement comprises: a mirror chamber within saidbase housing, said junction point lying within said chamber; a mirrormounted within said mirror chamber, said mirror having a mirrorreflecting surface intercepting said junction point; a continuous laserbeam pathway through said forearm, said tubes, said base housing, saidmirror chamber, and said turret housing, said beam pathway extendingcollinearly with said forearm axis, and said first and second wrist axesfrom a beam entrance end defined on said forearm, to a beam exit enddefined on said turret housing; first duct means enclosing said firstwrist axis and communicating with said mirror chamber and the innermostof said concentric drive tubes; first rotary slip joint means in saidfirst duct means for permitting said base housing to rotate with respectto said robotic forearm and said innermost of said tubes whilemaintaining enclosure of said first wrist axis; second duct meansenclosing said second wrist axis and communicating with said mirrorchamber and said turret housing beam exit end; and second rotary slipjoint means in said second duct means for permitting said turret housingto rotate with respect to said base housing while maintaining enclosureof said second wrist axis.
 5. A sealed-beam laser wrist and forearmassembly for a laser robot including:a base housing, rotatable about afirst wrist axis; a turret housing mounted to said base housing androtatable about a second wrist axis, transverse to, and intersectingsaid first wrist axis at a first junction point; a third wrist axis insaid turret housing, transverse to, and intersecting, said second wristaxis at a second junction point; a robotic forearm, rotatably supportinga plurality of concentric drive tubes, rotatable about a forearm axis;means for mounting said base housing to one of said drive tubes; meansfor rotatably driving said tubes; and means for drivingly-connectinganother of said drive tubes to said turret housing, said means fordrivingly-connecting including drive elements passing within said basehousing;wherein the improvement comprises: a first mirror chamber withinsaid base housing, said first junction point lying within said firstchamber; a second mirror chamber within said turret housing, said secondjunction point lying within said second chamber; a first mirror mountedwithin said first mirror chamber, said first mirror having a mirrorreflecting surface intercepting said first junction point; a secondmirror mounted within said second mirror chamber, said second mirrorhaving a mirror reflecting surface intercepting said second junctionpoint; a continuous laser beam pathway through said forearm, said tubes,said base housing, said first and second mirror chambers, and saidturret housing, said beam pathway extending collinearly with said first,second and third wrist axes from a beam entrance end defined on saidforearm, to a beam exit end defined on said turret housing; first ductmeans enclosing said first wrist axis and communicating with said firstmirror chamber and the innermost of said concentric drive tubes; firstrotary slip joint means in said first duct means for permitting saidbase housing to rotate with respect to said robotic forearm and saidinnermost of said tubes while maintaining enclosure of said first wristaxis; second duct means enclosing said second wrist axis andcommunicating with said frist and second mirror chambers; second rotaryslip joint means in said second duct means for permitting said turrethousing to rotate with respect to said base housing while maintainingenclosure of said second wrist axis; and third duct means enclosing saidthird wrist axis and communicating with said second mirror chamber andsaid beam exit end;whereby said laser beam pathway is maintainedenclosed with respect to said driving elements passing within said basehousing.
 6. The sealed-beam laser wrist and forearm assembly of claim 5,further comprising:a tooling plate, mounted to said turret housing atsaid beam exit end, said tooling plate rotatable about said third wristaxis; means for driving said tooling plate about said third wrist axis,said means for driving said tooling plate including drive elementspassing within said base housing; and rotary slip joint means in saidthird duct means for permitting said tooling plate to rotate withrespect to said turret housing while maintaining enclosure of said thirdwrist axiswhereby said laser beam pathway is maintained enclosed withrespect to said driving elements passing within said base housing.
 7. Asealed-beam laser robot forearm assembly for use with a laser wrist,having:a hollow-elongate forearm housing having opposite forearm ends; aplurality of concentric drive tubes rotatably journalled in said forearmhousing, on a common forearm axis; and drive means for independentlyrotating each of said concentric tubes;wherein the improvementcomprises: a continuous laser beam pathway through the innermost of saidconcentric tubes, extending from one forearm end to the other; means formounting a laser wrist assembly to one of said concentric tubes at oneof said forearm ends; rotary slip joint means formed around said forearmaxis in sealing engagement with said one of said concentric tubes; andlight pipe means at the other of said forearm ends for connecting saidinnermost tube with a laser light pipe system whereby said laser beampathway is enclosed and shielded from said drive means while said tubesare rotated.